The expression and significance of minichromosome maintenance protein 2 in colorectal adenoma and colorectal carcinoma

Abstract

Objective To explore the expression of minichromosome maintenance protein 2 (MCM2) in normal colorectal mucosa, colorectal adenomas and colorectal carcinoma, and to analyze the relationships among different histological types of colorectal adenomas and colorectal carcinoma. Methods Immunohistochemistry was used to exzamine the location and expression of MCM2 in the colorectal tissues, colorectal adenoma tissues and colorectal carcinoma tissues. Real-time fluorescent quantitative polymerase chain reaction (FQ-PCR) was used to detect MCM2 mRNA and connexin-32 mRNA expression. Results (1) Immunohistochemistry: The positive expression rate of MCM2 protein in normal colorectal mucosa, colorectal adenoma and colorectal carcinoma tissues was 16.7%, 55.0% and 80.0% respectively, with significant differences among them (P=0.031). The positive expression rate of MCM2 in tubular adenoma, mixed pattern of adenoma and villous adenoma was 40.0%, 65.0% and 75.0% respectively, also with significant differences among them (P=0.022). (2) FQ-PCR: The MCM2 mRNA expression in the normal colorectal mucosa, tubular adenoma, the mixed pattern of adenoma, villous adenoma, and colorectal carcinoma was 1.187±0.923, 4.126±1.339, 9.577±0.838, 22.150±4.077 and 48.020±4.811, respectively. The expression of MCM2 gradually increased in colorectal carcinoma, villous adenoma, the mixed pattern of adenoma, tubular adenoma, and normal colorectal mucosa (F=55.512, P=0.029). SNK multiple comparisons displayed that the differences about any two groups of the total mean showed statistical significance. Conclusion MCM2 is correlated with canceration of colorectal adenoma and the development of colorectal carcinoma. Detecting the expression of MCM2 can evaluate the progression of colorectal adenoma and the development of colorectal carcinoma. They may be the molecular biological indicators for predicting canceration of colorectal adenoma. Key words: Colorectal adenoma; Colorectal carcinoma; Immunohistochemistry; Minichromosome maintenance protein 2